Jimmy Fallon and Stephen Colbert sing about their friendship on ‘Late Night’

We all know the saying “keep your friends close, but keep your enemies closer.” But when it comes to the pair of Jimmy Fallon and Stephen Colbert, it’s tough to tell if their ties are as friends or foes.

But on "Late Night with Jimmy Fallon" Thursday night, these two feuding funnymen buried the hatchet with -- what else? -- a duet at the piano.

“Ivory and ivory, I can tolerate you and you don’t mind me,” they sang in unison to the tune of the famous Paul McCartney and Stevie Wonder collaboration “Ebony and Ivory.” The song continued with, “If Rihanna and Chris Brown can be friendly, why can’t we?”

Things weren’t always so hostile between the two TV personalities. After their ice cream duel brought them face to face, they declared themselves BFFSMs – Best Friends For Six Months. They also used their time as chums for good, raising $26,000 for DonorsChoose.org to help needy students. To boot, they chose to celebrate the milestone with one of their favourite best-friend activities: an on-air musical performance. Colbert gave an intense rendition of Rebecca Black’s YouTube hit “Friday” with The Roots as his backing band.

Now those six months of hatred are over as well, so 48-year-old Colbert and 38-year-old Fallon are at a crossroads over their true feelings. Thursday night, they seemingly decided that they consider each other “OK, I guess.”

“Ivory, ivory, two good friends we’ll someday be. Ivory, ivory, let’s agree to disagree,” they sang together as “Late Night with Jimmy Fallon” closed. Since this is one running joke without a six-month timeline, we’ll definitely see more of this dynamic duo.